Dipole Moment

Step 1: Understanding the Concept:
A molecule has a zero dipole moment if the vector sum of all individual bond dipoles cancels out, which happens due to its symmetrical geometry.

Step 2: Detailed Explanation:
• CH Cl : Tetrahedral but not symmetric (H and Cl differ). Net dipole moment is non-zero. • NH : Trigonal pyramidal. The lone pair causes a net dipole moment. • CH : Tetrahedral with identical C-H bonds. The vector sum of bond dipoles is zero. • PH : Similar to NH , has a net dipole moment.

Step 3: Final Answer:
CH has a zero dipole moment, which corresponds to option (C).